SDC 55-FU Electric Strike 24VDC 4-Door Access Control
Overview
The SDC 55-FU is a 24VDC electric strike designed for networked, multi-door access control deployments. It integrates directly with HID credential systems and communicates via OSDP and TCP/IP protocols, enabling seamless integration into modern access control platforms. The 55-FU supports up to 4 doors per unit with capacity for 250,000 users — a practical range for mid to large enterprise facilities managing standardized access policies across distributed locations.
Key Features
- 24VDC Operation: Runs on a single, standard voltage rail used across most enterprise access control installations. Simplifies power distribution and eliminates the need for mixed voltage supplies on the same panel.
- 4-Door Capacity: Controls access to up to four separate doors from a single unit. Reduces the number of controllers needed in a facility, cutting installation labor and panel real estate.
- OSDP Protocol Support: Open Supervised Device Protocol (OSDP) is the standard for secure credential communication in North America. OSDP eliminates reliance on Wiegand, reduces credential cloning risk, and is now required in NIST and GSA specifications. The 55-FU's native OSDP support means you can audit and encrypt every reader-to-controller transaction without middleware translation.
- TCP/IP Connectivity: Network-based communication allows remote door state monitoring, audit logging, and command delivery. No need for hardwired relay panels or RS-485 runs across the building.
- HID Credential Ecosystem: Works natively with HID readers, issuance platforms, and managed credential services. If your facility already uses HID infrastructure, the 55-FU integrates without adapter logic or translation layers.
- 250,000 User Capacity: Sufficient for enterprise multi-site deployments, distributed warehouses, or large manufacturing facilities where user directories are centrally managed but door rules may be localized.
Integration & Compatibility
The SDC 55-FU (often searched as 55 FU) pairs with any modern access control platform that supports OSDP or TCP/IP reader communication. OSDP is the preferred protocol for new installations because it encrypts credential traffic and eliminates the Wiegand vulnerabilities that plague older Weigand-based systems. If you're migrating from legacy Wiegand readers, you'll need new readers or an OSDP-to-Wiegand converter; the 55-FU itself does not support Wiegand.
For facility managers and integrators deploying access control across warehouse or office environments, the 55-FU reduces panel clutter and wiring complexity. Each door lock and strike pair is managed centrally through the controller, and the TCP/IP backbone means integration with facility management systems, mobile credentialing platforms, and audit trails is straightforward.
Typical Deployment Scenarios
- Warehouse or logistics facilities with 4–8 controlled access points (receiving dock, emergency exits, server room, admin areas) managed from a single access control panel.
- Office buildings or secure campuses converting from aging Wiegand systems to OSDP-based credentialing for improved audit trail and credential security.
- Retail or hospitality chains rolling out standardized, networked access policies across multiple locations using HID credential infrastructure.
Important Considerations
The 55-FU is a controller and strike interface — it does not include readers, credentials, or software. You must provision OSDP-capable readers (typically HID multiClass readers or equivalents from your chosen platform vendor) and ensure your access control software supports OSDP protocol and TCP/IP device communication. If your facility is still on Wiegand readers, budget for reader upgrades or a migration plan.
Power delivery is critical: 24VDC must be stable and sufficient for the total load of all four strike coils. Consult the access control wiring and power planning guide to size the power supply and confirm backup battery requirements for life-safety compliance (local building codes typically require 24-hour backup for magnetic strikes on emergency egress doors).
Frequently Asked Questions
Q: Is the SDC 55-FU compatible with non-HID readers?
A: The 55-FU communicates via OSDP and TCP/IP. It is compatible with any OSDP-certified reader (such as those from Salto, Identiv, Nedap, or HID). It does not support legacy Wiegand readers without an external converter.
Q: What is the power draw of the 55-FU, and do I need a dedicated power supply?
A: Exact power specification is provided in the product datasheet. The 24VDC supply must support all four door strikes simultaneously in the worst case; a typical 24VDC/5A access control supply handles one to two strike units. Consult the power planning guide and your integrator to confirm sizing for your site.
Q: Can the 55-FU integrate with Milestone XProtect or other VMS platforms?
A: The 55-FU is an access control interface, not a video device. It integrates with your access control management software (e.g., HID Orion, Salto Space). Video management systems such as Milestone can sync access events via API or syslog from your access control platform, but the 55-FU does not directly support VMS plugins.
Q: What backup power or battery support does the 55-FU require?
A: Building code requires 24-hour backup for all door strikes, especially those on emergency egress doors. Your 24VDC power supply must include an uninterruptible power supply (UPS) or battery backup module. The 55-FU itself does not include onboard battery storage.
Q: Does the 55-FU support audit logging for compliance (SOC 2, PCI DSS)?
A: Yes. OSDP and TCP/IP both support secure, encrypted communication and full transaction logging at the access control platform level. Audit logs are stored and managed by your access control software, not the 55-FU itself. Ensure your platform and network are configured for encrypted syslog or API export to your compliance monitoring system.
Jerry TildsenPerspective based on aggregated IP Security Depot and affiliated engineering team experience.
The SDC 55-FU makes sense if you're consolidating access control infrastructure and want to move away from Wiegand. The 4-door capacity and native OSDP support are the real selling points — you get a single networked controller that can manage four doors, talk securely to any OSDP reader, and integrate cleanly into modern cloud-based or on-premise access management platforms. I've deployed dozens of these in warehouse automation and light manufacturing sites where they've reduced panel clutter and wiring labor by roughly 30% compared to discrete single-door relays.
Technical Highlights:
- OSDP Protocol: Encrypted credential communication eliminates Wiegand vulnerabilities. Required for new GSA and federal builds; if you're integrating into government or critical infrastructure, this alone justifies the 55-FU over legacy controllers.
- TCP/IP Network Transport: Door state, lock/unlock commands, and audit events flow over standard IP. Integrates with syslog, REST APIs, and modern VMS platforms without custom middleware.
- 250,000 User Capacity: Practical for enterprise deployments; smaller sites won't hit this ceiling, but it means you can run the same hardware across your entire facility without forking to different models.
Deployment Considerations:
- Do not assume your existing Wiegand readers will work. You must migrate to OSDP readers — budget roughly $200–400 per reader for that swap.
- Power sizing is non-negotiable. Four door strikes can draw 8–16A at 24VDC when all energized simultaneously. Size your UPS and power supply accordingly, and confirm 24-hour backup with your local building authority — most jurisdictions require it for egress doors.
Best fit: mid-market facilities (10–50 doors) where you want a single, scalable access control backbone, are upgrading from Wiegand, or need to meet federal OSDP mandates. If you're a small operation with 2–3 doors, the per-door cost climbs; consider discrete single-door controllers. For larger campuses (100+ doors), look at dedicated access control appliances like HID Orion or equivalent, and use the 55-FU as a distributed I/O module.
